False-Positive Amphetamine/Ecstasy (MDMA/3,4-Methylenedioxymethamphetamine) (CEDIA) and Ecstasy (MDMA/3,4-Methylenedioxymethamphetamine) (DRI) Test Results With Fenofibrate

Abstract

This case report describes a false-positive amphetamine/ecstasy [3,4-methylenedioxymethamphetamine (MDMA)] and ecstasy (MDMA) screen after therapeutic use of antihyperlipidemic drug, fenofibrate. A 60-year-old male patient was admitted to inpatient psychiatry unit with the diagnosis of alcohol dependency. He was prescribed diazepam 30 mg/day, thiamine 300 mg/day, and naltrexone 50 mg/day. He had also been using fenofibrate 267 mg/day for 3 years for hyperlipidemia and trazodone 100 mg/day for 5 months for insomnia. On routine, urine drugs-of-abuse screening amphetamine/MDMA (CEDIA) test was positive for 4 different occasions and MDMA (DRI) test was positive on 5 different occasions. Gas chromatography/mass spectrometry confirmation of the first positive 3 samples were negative for amphetamine and MDMA. After discontinuation of fenofibrate, amphetamine/MDMA, and MDMA immunoassay results turned out to be negative. Caution should be given to interpretation of amphetamine/MDMA (CEDIA) and MDMA (DRI) tests in patients taking fenofibrate. Specific confirmation with a suitable method should be used to prevent erroneous interpretations.

Rapid label-free determination of ketamine in whole blood using secondary ion mass spectrometry

“…Compounds with structures similar to the target drug interfere with the results of immunoassays. The amounts of drugs cannot be accurately measured, which leads to prevalence false positive reports or, more importantly, false negative screening results [11][12][13]. Therefore, a second analytical method, a chromatographic separation (gas chromatography (GC) or liquid chromatography (LC), typically)-mass spectrometry (MS), has been developed either as a complement to immunoassays in clinical testing or as the analytical method in forensic and doping control applications [14][15][16][17][18][19].…”

Guilty or not guilty? — False positive results of common medicines in drug tests: review and practical guide

“…Esmolol Homogeneous enzyme immunoassay Abbott MULTIGENT® (500 μg/L) 237,300 μg/L 2 [15] [22] [23] Esmolol acid Homogeneous enzyme immunoassay Abbott MULTIGENT® (500 μg/L) 446,400 μg/L 2 [15] Famprofazone CEDIA immunoassay (N.M.) 100 mg -6 h before test 1 [24] Fenfluramine Amphetamine immunoassay screens (N.M.) [20] Fenofibrate amphetamine/MDMA CEDIA (1000 μg/L) daily dose of 267 mg 1 [25]…”

“…Fibrats: Fenofibrate also shows an F/P result for amphetamine in some studies [25,26]. One of them a 60-year-old male patient with a history of alcohol dependency was admitted to an inpatient psychiatry unit.…”

Variability amongst urine toxicology amphetamine readings with concurrent administration of fenofibrate

“…It is believed that fenofibrate, or a metabolite of it, has a molecular structure bearing similarity to amphetamine which may produce false-positive UDS readings. 8–11 In these research articles, mass spectrometry was used as a gold standard to confirm or refute presumptive positive results based upon the initial UDS.…”